(a) Field of the Invention
This invention relates to treating of unwanted and unburned carbon in fly ash and more particularly, but not by way of limitation, to an apparatus and process for removing the carbon by heating the fly ash up to 1200 degrees F. in a heating chamber.
(b) Discussion of Prior Art
Heretofore there have been a variety of different types of methods and apparatus used in treating fly ash. U.S. Pat. No. 5,160,539 to Cochran, discloses a method and product of fly ash benefication wherein fly ash with carbon is oxidized in a bubbling fluid bed of the same material and mixed with air at temperatures in a range of 1300 to 1800 degrees F. U.S. Pat. No. 5,207,164 to Breen et al. describes a process for limiting the production,of fly ash in the bottom of a boiler. The fly ash is carried in a gas stream where it is exposed to a flame heat prior to being dropped into an ash pit.
U.S. Pat. Nos. 3,374,101 and 3,328,180 to Ban describes two different methods of treating fly ash to remove the carbon therein. One method treats fly ash pellets to progressive heat exposure and the other method treats the fly ash by forming discrete green pellets and then drying and firing pellets at temperatures up to 2400 degrees F. U.S. Pat. No. 4,705,409 to Trerice discloses a method and apparatus for reducing and measuring carbon content in fly ash. The invention as described in this patent employs microwave energy as a method of heating the fly ash.
None of the above mentioned patents describe the use of a stainless steel heating chamber heated in a range of from 800 to 1200 degrees F. wherein fly ash is introduced at one end of the heating chamber and moved slowly to an opposite end by an auger. The auger is used to mix the fly ash with oxygen. When the carbon in the fly ash is burned in the heating chamber the carbon acts as a fuel in combination with the oxygen for heating the fly ash and removing the unwanted carbon in the fly ash.